1. The Field of the Invention
The present invention relates generally to drill rods, such as drill rods for percussive drilling, and their method of manufacture. More specifically, the present invention relates to bi-steel percussive drill rods.
2. Related Technology
Drill rods are known in the art and are used in drilling operations including percussive drilling. In percussive drilling, drill rods and other drill components are subject to high levels of impact, local-working, and bending stresses associated with the drilling process. Accordingly, structural steels can be employed in the manufacture of drill rods to withstand the associated stresses. However, these structural steels can contain expensive alloying elements such as nickel to achieve the desired mechanical properties. While alloying materials were once available more abundantly, supplies are now strained by high demand. As a result, the prices of alloying elements are ever increasing, causing the cost of manufacturing drilling components such as drill rods to increase as well. This, in turn, presents a financial burden for drilling companies and manufacturers.